This invention broadly relates to an improved vehicle air bag safety system. More particularly this invention relates to a unique cover mechanism adapted to open in a predetermined manner when the air bag itself is deployed.
The state of the art is indicated by the following references cited:
______________________________________ Patent No. Issue Date Inventor(s) ______________________________________ 3,819,205 June 25, 1974 Dunford et al. 3,837,669 September 24, 1974 Nagazumi et al 3,853,334 December 10, 1974 Auman et al. 3,887,215 June 3, 1975 Albrecht et al. 3,907,330 September 23, 1975 Kondo et al. 3,982,774 September 28, 1976 Ivashuk et al. 4,148,503 April 10, 1979 Shiratori et al. 4,325,568 April 20, 1982 Clark et al. 4,334,699 June 15, 1982 Patzelt et al. ______________________________________
There are already known steering wheels for motor vehicles that are provided with air bag cushions designed to convert from a folded inoperative position into an inflated operative position in order to cushion the vehicle operator in the event of a collision. The air cushion in its folded condition is connected through its bottom edge to a gas generator mechanism equipped with a diffuser section and attached to the steering wheel hub. The cushion is located in a recess in the central portion of the steering wheel and is held in position by a cover member. It has also been known in the past that an air bag installation may be used, for a conventional left-hand drive vehicle, wherein the vehicle occupant sitting in the right front seating position may be protected by an air bag that is deployable from a housing in the dashboard or instrument panel generally in front of the right-front seating position.
In the past, cover members have been used on air bag installations, wherein the cover member was made of an outer layer which was formed of a molded plastic (e.g. urethane) with a fibrous reinforcing mat placed within the plastic layer. This latter type of construction, which has been used commercially for the past several years, has had certain problems associated therewith. For example, it was difficult to manufacture such an air bag cover construction because, in the molding operation itself, it was very troublesome to place the fibrous reinforcing mat within the plastic material at or shortly before the time of molding. Secondly, the fibrous reinforcing fabric itself had to be sewn from small separate pieces and that was difficult, time consuming, and very expensive to do. Third, the fibrous fabric reinforcing material was very porous, and due to that high porosity it resulted in large amounts of entrapped air being left in the molded cover member; and then when the fabric was placed in the mold for molding the urethane material over it, the pressure of the incoming urethane would cause the air to be released; and, this would cause air voids on the surface of the plastic cover member which led to numerous rejects of the cover members being manufactured. Fourth, the fibrous fabric reinforcing material, being flexible, would sometimes tend to float within the mold as the molding operation was being carried out; and, this would result in the fabric more or less floating to the surface of the cover member causing blemishes on the decorative surfaces of the outer cover member, for example, on the decorative surface of the hub area of a steering wheel. Fifth, the fibrous fabric reinforcing material offered no structural support for the urethane make-up of the cover member; and, when the urethane was molded over the fibrous fabric reinforcing material there often later occurred some shrinkage in the urethane, and this caused a distortion in the outside shape of the finished urethane part.
Accordingly it is an object of this invention to provide a new and improved air bag product for motor vehicles.
Another object of the present invention is to provide a new air bag safety system for motor vehicles wherein the air bag installation is hidden from view by a unique air bag module cover.
Another object of the present invention is to provide a new air bag safety system wherein the module which makes up the air bag installation is covered by a new and unique plastic cover member which rips open in a safe and reliable manner when the air bag is deployed.
Another object of the present invention is to provide a new air bag safety system wherein the module which makes up the air bag installation is covered by a new and unique plastic cover member which rips open in a safe and reliable manner when the air bag is deployed.
Another object of the present invention is to provide a new air bag safety system for motor vehicles wherein the module which makes up the safety system is covered by a special air bag modular cover product.
Another object of the present invention is to provide a new air bag cover which is comprised of a thermoplastic molded inner-reinforcement layer and a second layer of a soft polyurethane foam material formed by a reaction injection molding process directly onto and in covering relation with the inner reinforcement layer, the center area of the air bag cover having a gap in the inner reinforcement layer; and the cross-section of the urethane at the gap being of reduced cross-section and thus relatively thin whereby to thus form a tear seam in the cover.
Still another object of the present invention is to provide a new and unique air bag cover wherein the cover member contains a thermoplastic reinforcement layer, to which the urethane is strongly adherent, which prevents inadvertent release of the urethane portion of the cover when the air bag is deployed.